div{
    width: 200px;
    height: 200px;
}
.h{
    background-color: red;
    position: relative;
    margin:100px auto 0 auto;
    transform: rotate(45deg);
    animation-name: ms;
    animation-duration: 1s;
    animation-iteration-count: infinite;
    animation-direction: alternate;
}
.a{
    background-color: red;
    position: absolute;
    top: -100px;
    border-radius: 100px;

}
.b{
    background-color: red;
    position: absolute;
    left: -100px;
    border-radius: 100px;
}
@keyframes ms {
    0%{
        transform: rotate(45deg) scale(0.2);
    }
    50%{
        transform: rotate(45deg) scale(0.4);
    }
    100%{
        transform: rotate(45deg) scale(0.9);
    }

}